<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
    </head>
    <body>
        <script>
            function log(str){
                return new Promise((resolve,reject)=>{
                    setTimeout(()=>{
                        resolve(str);
                    },10)
                })
            }
            async function runLog() {
                var str="";
                const str1 = await log('hello');
                console.log(str1)
                const str2 = await log('lagou');
                console.log(str2)
                const str3 = await log('I ❤ U');
                console.log(str3)
                console.log( str1+str2+str3 );
            }
            runLog();
        </script>
    </body>
</html>
